Small Engine Guru's

ehenry

ehenry

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I have a 6.5 horse horizontal shaft Techumse XL engine on a Troybuilt tiller. The engine cranks and runs fine, has 110 lbs. compression. The problem I'm having is that it blows oil out the crankcase vent on the valve cover on the side of the block. Having the amount of compression it does I wouldn't think that it would have that much blow-by. It blows so much oil out that you can only run it about 15 to 20 minutes before you have to fill it back up. Anyone got any thoughts on this???
 
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SlowlySinking

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Re: Small Engine Guru's

The Tecumseh manual under problems; "Breather Passing Oil" says; engine speed too fast, loose oil cap or oil cap gasket damaged or missing, oil level too high, breather mechanism damaged, drain hole in breather box clogged, piston ring gaps alignment, breather mechanism installed upside down, damaged or worn oil seals on crankshaft, rings not properly seated, breather assembly not assembled correctly, cylinder cover gasket leaking. Pick a few and go for it, good luck.
 
ehenry

ehenry

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Re: Small Engine Guru's

SlowlySinking, you just happen to have a Tecumseh manual or did you find it on line? I've changed the breather mechanism around twice, that didn't help any. Ran it without it and that seemed to help some but it still passed oil. I've checked the hole in the breather box and it's open. It isn't the oil level because it pukes it out till its empty. I'll check the gasket on the oil fill cap. Now as far as the seals on the crank and the rings....the old dude I bought the thing from said he had just had it rebuilt and only ran it a couple times since he had it rebuilt but he didn't notice it puking oil out. He did tell me he'd give me my money back if I wanted it but I guess I'm gonna hang on to the tiller since I only gave him $100 bucks for it. If nothing else I'll have a project this winter to rebuild the little engine. Its a cast iron block so it can be bored. Worse come to worse I'll buy an engine for it. I know if I tried to buy that tiller new it'd be over a grand.
 
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SlowlySinking

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Re: Small Engine Guru's

Hi efhenry, I just happened to have it. I bought it when I rebuilt my mower engine about 15 years ago. It's for the 3-10 HP light & medium frame engines. The manual doesn't list normal compressions. Given a recent rebuild and your compression reading I would assume that the rebuilder installed something incorrectly and I would start with the breather unit, the manual has a picture of the breather assembly, check the part that has the group of holes and fits slightly inside and against the block, the holes should be at the top, next goes the filter element, then the gasket, then the cover with the rubber tube hole placed up to the top, the manual also says that some engines had two gaskets installed next to the engine block, if so replace with two. Or, it could be something as simple as the oil filler casket missing/leaking. At the price you paid you can't lose, good luck,,
 
ehenry

ehenry

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Re: Small Engine Guru's

That breather element is a little box looking thing with one big hole on the back side of it, then on the front side theres a group of 9 little holes that are to one side of the element. The hole for the rubber tube is in the middle of the cover and runs to the air-filter box. It puke so much oil out that it filled the air filter up and started sucking it back in to the carburator. At any rate i appreciate you getting back to me on this.
 
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SoulWinner

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Re: Small Engine Guru's

Ahhh...just rebuilt it eh? I would bet the ring gaps are all lined up. The high compression may contradict this however. Not sure, but I have seen this several on rebuilt car engines (never done it myself......really)
 
ehenry

ehenry

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Re: Small Engine Guru's

The old dude I bought it from also said the machine had been sitting up for a while too. I had to go through the carburator to get it where it would crank. I'm wondering if the rings may have seized or something like that. I pulled the sparkplug out and brought the piston TDC on the compression stroke then poured some Seafoam in and let it sit for a couple days. The Seafoam eventually made it down in to the crankcase. I changed the oil and added a couple capfulls of Seafoam to the oil and ran. Still pukes the oil out. It is entirely possible the ring gaps are lined up depending on if whoever rebuilt it was experienced or not.
 
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jee70611

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Re: Small Engine Guru's

Have you actually traced the little rubber tube back to the block. If I remember right, there is a pcv valve on the block. I know that on some of the vertical shaft tecumseh's I've worked on, the pcv valve is under the flywheel. I'm not sure about yours though. Trace that little rubber tube from the breather to the pcv valve. Take the valve off and shake it. It should rattle. If not replace it or you may be able to clean it with gas or something. I've had a Briggs and Stratton do exactly what your's is doing and that was the problem. Those little engines are pretty much the same so I would guess that is your problem. Good Luck and let us know what you find out.<br /><br />James
 
Kenneth Brown

Kenneth Brown

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Re: Small Engine Guru's

Not exactly relating to your problem but helpful info. Troy-built uses a brass/bronze gearset in the tranny and box. Be sure and check the fluid EVERY TIME BEFORE USE. They are bad about leaking and running low. My inlaws gave me a 8 HP tiller that had run low. My father in law is almost anal about P M so this suprised me greatly. The parts were extremely hard to find and not cheap at all. One worm gear and a seal was $149 plus $65 labor. They use a 140 weight lube if not mistaken. The 85-140 will not work, must be straight 140. I keep mine checked and it never gives any problems, best unit I have ever seen. Good buy you got there.
 
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SlowlySinking

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Re: Small Engine Guru's

If I read you right it sounds like the breather is installed wrong, is the hole for the rubber tube centered side to side and top to bottom or offset? Does the part with the 9 holes mount with the long side vertical or horizontal, the manual shows vertical? If vertical the part with the 9 holes should be installed with the 9 holes against the block and with the 9 holes closest to the top of the engine and then the filter covering the 9 holes. Let's verify this and then continue on. Ken
 
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norman158

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Re: Small Engine Guru's

pull the head and check the exaust valve guide
 
ehenry

ehenry

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Re: Small Engine Guru's

Ken, the breather installs horizontally and will only install two different ways. Looking at the engine the part with 9 holes will be facing you. When you install it one way the 9 holes will be on the left or flip it over and they will be on the right. It will not intall any other way. The hose that goes to the airbox from the valve cover in dead in the center of the valve cover. I checked the gasket on the oil fill cap/dipstick and its fine. This engine could be a different model and type from manual that you have.<br /><br />Ken Brown, thanks for the info on the transmission...this machine is pretty old and the transmission leaks like a siv...have to checkit everytime I use it. HOWEVER, all the seals install from the outside rather than from the inside of the gear case so i should be able to rob them out and replace them fairly easily. Just get the numbers off them and cross reference with another make of seal.
 
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SlowlySinking

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Re: Small Engine Guru's

efhenry, I downloaded all 5 manuals from the web site noted above, the XL manual section on breathers amazingly doesn't show a horizontal breather assembly, only vertical, apparently they used a stock illustration of a breather. In your case since the breather hose is dead center I would look at the block, is one end of the cutout different from the other? Or install it one way, make sure the filter element is over the 9 holes, run the engine, then reverse the cover, see if one way stops the oil blowing out, if not then I would logically assume that's not the problem. If you want I will burn all 5 Tecumseh manuals and Adobe reader 6.xx on a CD and ship it to you at no charge, if yes, give me your e-mail address and I will e-mail you for your street address, it's bad enough with your e-mail on a public forum, I prefer to not street addresses on a public forum. One way to prevent web crawlers from grabbing your e-mail address is to add some random word in parathenses in the address, Ken
 
ehenry

ehenry

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Re: Small Engine Guru's

I replaced all the seals on the tiller (tine seals, wheel axle seals and main shaft seal) over the winter. <br /><br />I never could stop the engine from blowing oil out the vent. SO , I purchased a new 8 horse Tecumseh engine for it to replace the 6 horse. I should get it sometime next week.
 
Mark42

Mark42

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Re: Small Engine Guru's

Did you get a new breather from the parts store? It sounds like the internal valve is shot. For a few bucks I would put in a new one and see what happens.
 
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